Astroparticle Physics

52 4 Physics of Particle and Radiation DetectionTable 4.1Overview of interaction processesof charged particlesTable 4.2Overview of interaction processesof photonsenergy-loss dependence− dEdx∣ = Kz 2 Zion A× 1 {1β 2 2 ln 2m ec 2 β 2 γ 2 T maxI 2 − β 2 − δ 2, (4.6)whereK – 4πN A re 2m ec 2 ≈ 0.307 MeV/(g/cm 2 ),N A – Avogadro’s number,r e – classical electron radius (≈ 2.82 fm),m e c 2 – electron rest energy (≈ 511 keV),z – charge number of the incident particle,Z,A – target charge number and target mass number,β – velocity (= v/c) of the incident particle,γ – 1/ √ 1 − β 2 ,2m e p 2T max –m 2 0 + m2 e + 2m eE/c 2maximum energy transfer to an electron,m 0 – mass of the incident particle,p, E – momentum and total energyof the projectile,I – average ionization energy of the target,δ – density correction.The energy loss of charged particles, according to theBethe–Bloch relation, is illustrated in Fig. 4.2. It exhibitsa1/β 2 increase at low energies. The minimum ionizationrate occurs at around βγ ≈ 3.5. This feature is called the}